5 Common Metal Enclosure Exterior Finishes

When a telecommunications or networking organization is considering an enclosure, their biggest considerations revolve around the construction of the cabinet/shelter and how well it protects their equipment. In the consideration phase, those organizations should also give some thought to enclosure exterior finishes.

The exterior finish of a metal enclosure can affect more than just the aesthetics of the cabinet. It can cause the enclosure to be less or more expensive, raise the R-value and help ensure the longevity and durability of an enclosure.

So, here are the five most common metal enclosure exteriors in the telecom industry, and the pros and cons of each.


Bare Aluminum

Bare aluminum enclosures are somewhat common in the industry and offered by some of the leading enclosure manufacturers.

On the pro side, bare aluminum is the least expensive option for metal enclosures. It offers decent corrosion resistance, as long as the cabinet isn’t deployed too close to saltwater, a refinery or any other environment known for being corrosive and causing discoloration and oxidation.

One of the biggest negatives of a bare aluminum cabinet is the aesthetics–there is nothing hiding every scratch and blemish the panels will get during production, shipping and installation. Plus, bare metal is never as easy to clean and brighten up as painted metal, so it will be harder to keep your enclosure looking good in locations where aesthetics matter.

In summary, if an organization wants to save money, doesn’t care as much about overall looks or heat transfer and the enclosure won’t be in a highly corrosive environment, bare aluminum is a solid choice.


Stainless Steel #4

#4 refers to the brushed finish that is common on stainless steel–it’s the finish you see on most stainless kitchen products. This means that the enclosure isn’t painted, so you see the brushed stainless steel exterior.

Cabinets with this exterior have a number of positive aspects to them. For one, stainless steel is very corrosion resistant. If an organization wants to put a cabinet in a very corrosive environment, e.g., a coastal region, they will want a cabinet with a NEMA 4x rating (4 indicates that the cabinet protects against water ingress, x denotes enhanced corrosion resistance). Stainless steel is one of the two ways to get that rating–galvanized or bare aluminum won’t cut it. In addition to its corrosion resistance, stainless steel offers a nice finish that will reflect sunlight, helping keep the interior cool.

Negatively, stainless steel cabinets are more expensive than their aluminum counterparts, even without an exterior coating. Plus, like aluminum, while it looks great when it’s done right, it’s a challenge for manufacturers who weld their cabinets because after welding, they have to blend the welds to match the #4 finish. If they bolt their cabinets together, this isn’t an issue, but you’re also not going to get that NEMA 4x rating because of the bolted construction.

Another con is that if the cabinet is going in an area that is hot, heat transfer needs to be taken into account. A stainless steel cabinet will transfer the heat from outside in, which can harm equipment. This issue will also apply to bare aluminum cabinets.

So, stainless steel #4 is expensive, but extremely tough and corrosion-resistant.


Powder Coating

Any major enclosure manufacturer who offers “painted” cabinets uses powder coating on their cabinets, not liquid paint.

Powdercoating offers a number of advantages over other finishes. For one, it’s extremely durable. To apply powdercoating, companies have to use a multistep process to clean and pre-treat the metal to ensure proper powder adhesion. After the powdercoating is baked on, it creates a very tough finish that is chip and corrosion-resistant. Unlike bare metal, powdercoat is very easy to clean if needed, making it ideal for areas where aesthetics matter.

Like stainless steel, powdercoated aluminum is extremely corrosion resistant–this is another way to get a NEMA 4x rating.

In addition, while tan and beige are the standard colors in the telecom industry, many manufacturers offer a variety of colors to consider. Lighter colors will reflect solar heat, which helps keep the interior cool and protect equipment.

The only real con to a telecom customer is that if the powdercoating gets scratched or messed up in the field somehow, it can’t be touched up with powder. Instead, the company will have to use a matching liquid paint to touch up the problem area.

Otherwise, the cons go to the manufacturer, who has to invest a significant amount of money, space and resources to set up their facility for powdercoating. The entire process differs from manufacturer to manufacturer, but it always requires multistage wash capabilities, long lines for transporting parts and massive ovens for baking on the powder.

With few negatives, it’s no wonder it’s the most common exterior finish choice in the telecom industry.



Aggregate is a composite gravel-studded panel that is secured to the exterior of an enclosure (generally a shelter, not smaller cabinets) with screws and weather-resistant tape.

The only real plus to aggregate is its looks. Many organizations find it visually pleasing, and some municipalities require it in place of the other enclosure exterior finishes on walk-in shelters.

There are quite a few negatives to aggregate, though. For one, it’s more expensive than other exterior options. It doesn’t offer any notable R-value or ballistic ratings. It’s hard to work with if an organization isn’t properly equipped with tools like waterjet cutters.

In addition, aggregate will “shed” gravel over time. While not a huge deal, it can be rather frustrating to visit one of your sites and see that the panels you paid extra for are losing their pieces on the ground.

Finally, there are few organizations that produce aggregate panels for enclosure manufacturers. In times when supply chain issues are common across all industries, it can take much longer for a manufacturer to receive those panels, which can result in extensive delays in delivering enclosures.

All in all, when it comes to enclosure exterior finishes, aggregate is purely an aesthetic choice, and an expensive one at that.


Rubberized Coating

While all the previous finishes discussed are for the walls of an enclosure, there is a noteworthy roof finish to be aware of–rubberized coating.

This special coating offers nothing but pros to the customer. For one, it’s standard on many walk-in shelters. Plus, it’s highly reflective so it helps keep the enclosure interior cool. And, it helps seal up the roof and top edges, minimizing the chance of leaks.

The cons only apply to the manufacturers, but even they recognize that the pros (less service calls due to leaky cabinets) outweigh the cons (the cost of the material).


At American Products, we offer many of the above enclosure exterior finishes. But, we’re extremely proud of our powdercoating. Unlike some manufacturers, we go the extra mile with a SIX-stage pretreatment to ensure maximum adhesion. Not only does this help our cabinets meet the Telcordia standards for 720-hour corrosion resistance, we surpass it. We’ve actually seen our cabinets go over 1,000 hours on a regular basis!

If you’re interested in learning more about American Products telecommunications and networking enclosures and how we can help protect your network, contact our enclosure experts at 417.323.6312 now.

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